Playable on PC, PS4, and Xbox One at some point
Bethesda has updated its FAQ for the Doom beta, which you might recall is being included as a pack-in for Wolfenstein: The New Order. ("Please buy our game!") Most notably, the beta will be playable on PC, PlayStation 4, and Xbox One only, meaning if you buy Wolfenstein for Xbox 360, for instance, you'll receive beta access on Xbox One. Sorry, Ouya owners.
The other thing that jumped out at me in between the non-answers saying to check back later for more information is the fact that Xbox Live Gold is required to play the beta while PlayStation Plus is not. I mean, guess I should've seen that coming, but I still find it to be so silly.
Are you thinking of getting Wolfenstein for the Doom beta? Although I want more Doom in my life -- more good Doom, I should say -- there are too many unknowns at this point for me to commit.
Updated Wolfenstein Pre-Order FAQ w/ DOOM Beta [Bethesda Blog]